Experimental Study And Numerical Simulation Of Geotextile Gravel Piers

With the development of the society,the construction industry has also developed rapidly.The area of soft soil in China is widely distributed,More and more buildings are built on weak land bases,and the soft soil foundation construction process is constantly updated.The ordinary broken stone pier is prone to bulge deformation under the action of vertical load.To give full play to the broken stone bearing potential and advantages,Within a certain length of the piers,the soil cloth bags are wrapped into the broken stone blocks,the lateral deformation of the pier is restricted,the bearing capacity of the composite foundation is improved,and the bearing capacity of the crushed stone pier is given full play.The composite foundation of the pile was selected for the study of the silty clay layer in the foundation.By using the method of pre drilling and vibroflotation,the consolidation of silt silty clay with bag rubble pier composite foundation is carried out.The contents and conclusions of this paper are as follows:(1)Select the test areas and arrang three test sites.Test No.1 is the test of 800 mm rock bag rubble mound pier without geotextile,test No.2 is the test of 800 mm rock bag rubble mound pier with geotextile,test No.3 is the test of 1200 mm rock bag rubble mound pier with geotextile.All three trials reinforce the foundation by the method of the pre hole deep tamping bag rubble pier and the deep hole vibrating bag rubble pier with preformed hole.(2)Test the compactness of the pier body by the super heavy dynamic penetration test.The conclusion is that the upper part of the pier is loose in the range of about 3m.Comparing the average strike number of pre-hole deep tamping bag rubble pier and pre-hole deep vibrating bag stone pier,the conclusion is that the pier body formed by vibrating bag pier method is more compact and the side effect of geotextile bag for Macadam pier is remarkable.(3)The characteristic value of single pier compressive bearing capacity is determined through the plate load test,the single pier compressive bearing capacity test was carried out in the three test areas,the conclusion is that full tamping can improve the bearing capacity of pier and reduce the settlement and the larger the pier diameter of geotextile bag macadam pier is,the greater the compressive bearing capacity of the pier body and in the depth range of 2 to 3D(D is pier diameter),the higher the density of pier body,the greater the vertical bearing capacity of single pier.(4)Using PLAXIS software,taking the stiffness of geotextile bag as variable quantity and carry out numerical simulation of settlement and radial deformation(150kPa and 200kPa),the conclusion is that stiffness has obvious effect on reducing settlement and radial deformation.Taking the wrapping length of different geotextile bags as variable quantity and carry out numerical simulations of settlement and radial deformation(200Pa and 250kPa),the conclusion is that the increase of the length of the parcel is beneficial to the settlement and deformation control.